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When Traffic Class not mapped to egress queue but class defined under classifier

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  • 1.  When Traffic Class not mapped to egress queue but class defined under classifier

    Posted 09-05-2017 12:54

    Hi everybody,

     

    Please consider the following set up:

     

    Let say if we have classifier JOJO on EX 4300

    010000—Class B

    011000-Class C

     

    Forwarding class mapping:

    Class C---Queue1

    This classifier applies to ge 1/1/0.0

    Let say a packet with DSCP 010000 received on the ge 1/1/0.0, Classifier JOJO is used to classify this packet but we do not have egress queue mapped to this class, what will SW do ? Will it place this packet into default queue since there is no mapping between ClassB and queue?

     

     

    Thanks and have a nice day!!

     



  • 2.  RE: When Traffic Class not mapped to egress queue but class defined under classifier
    Best Answer

    Posted 09-06-2017 23:06

    Yes that is correct. Classifier is really telling the software what you would like it to do with the packet. But it does not change any fields in the packet header. The marking is applied only with the rewrite rule, so without a matching re-write rule the default will be applied based on th einterface and the device. SRX and Switch have different default and depending on interface type (trunk/access).

    The classifier is like a gateman who peeks in the door and say SAM is a VIP, I am giving him a card that you should stamp him with #9 (forwarding class) and send him to booth  9 (queue) where he can get MOET and whatever else(special treatment). But only the Manager (rewrite-rule) can do that. Without the Manager and the stamp(marker for the forwarding class mentioned in the rewrite rule ), he only has the card telling the Manager what to do. But no Manager is there to do it. So he just defaults to the bar. First come first served:) i.o.w the card (classifier) means zilch without the Manager(re-write rule).



  • 3.  RE: When Traffic Class not mapped to egress queue but class defined under classifier

    Posted 09-08-2017 08:31

    Thanks

     

    Thanks Lyndidon, have a nice Weekend!!



  • 4.  RE: When Traffic Class not mapped to egress queue but class defined under classifier

     
    Posted 09-08-2017 09:14

    Agree - I thought that was an EXCELLENT response!!



  • 5.  RE: When Traffic Class not mapped to egress queue but class defined under classifier

    Posted 09-08-2017 09:48
    YW. U2:)